The use of dielectric rod antennas has previously only been known from the field of radar technology.
A UWB antenna is thus known from the publication “Compact, dual polarized UWB antenna, embedded in a dielectric”, Grzegorz Adamiuk et al., IEEE transactions on antennas and propagation, Volume 56, No. 2, February 2010, in which a dual-polarized antenna composed of two slot radiators is arranged in a dielectric body in the form of a cone.
The publication “An ultra-wideband dielectric rod antenna fed by a planar circular slot”, Mario Leib et al., IEEE transactions on microwave theory and techniques, Vol. 59, No. 4, pages 1028-1089, April 2011, likewise shows a UWB antenna having a dielectric rod antenna that is fed by a slot radiator.
The publications “Wideband Dual-Circularly-Polarized Dielectric Rod Antenna for Applications in V-band Frequencies”, M. W. Rousstia et al., Proceedings of ICT.OPEN 2013, 27-28 Nov. 2013, Eindhoven, Eindhoven Technical University, 2013, “High performance 60-GHz dielectric rod antenna with dual circular polarization, M. W. Rousstia et al., Proceedings of the 10th European Radar Conference, (EuRAD), Oct. 9-11, 2013, Nuremberg, IEEE, pages 359 to 362, and “NEW METHOD FOR ULTRA WIDE BAND AND HIGH GAIN RECTANGULAR DIELECTRIC ROD ANTENNA DESIGN”, Jingping Liu et al., Progress In Electromagnetics Research C, Vol. 36, p. 131-143, 2013, likewise show the use of dielectric rod-like bodies in the field of radar technology.
In the cellular radio field, it is only known with group antennas composed of a plurality of dipole radiators to arrange thin dielectric plates of low relative permittivity on the individual dipole radiators.
Dielectric resonator antennas are furthermore known in the cellular radio field in which the dielectric body itself is used as the radiator that is typically fed via a slot.
It is the object of the present invention to improve the properties of cellular radio antennas and in particular their usability in cellular radio antenna arrangements having a high single radiator density.
This object is achieved in accordance with the invention by a cellular radio antenna having at least one dipole radiator and having a dielectric body arranged on the dipole radiator, wherein a height of the dielectric body in a main radiation direction amounts to at least 30% of a maximum thickness of the dielectric body in a cross-section perpendicular to the main radiation direction. Embodiments of the invention form the subject of the dependent claims.
The present invention shows in a first aspect a cellular radio antenna, in particular a cellular radio antenna for a cellular radio base station, having at least one dipole radiator and having a dielectric body arranged on the dipole radiator. The present invention is characterized in that the height H of the dielectric body in the main radiation direction amounts to at least 30% of the maximum thickness D of the dielectric body in a cross-section perpendicular to the main radiation direction.
The dielectric body acts as a waveguide for the cellular radio signals emitted by the dipole radiator due to the dimensioning in accordance with the invention and hereby displaces the radiation plane of the dipole radiator. The displacement of the radiation plane in particular means the changing and/or displacing of the effective radiator aperture and/or the displacement of the phase center of the radiation in the main radiation direction. This allows a plurality of new areas of application of the combination of dipole radiators and dielectric bodies, in particular in the field of cellular radio antenna arrangements having a plurality of antennas.
In this respect, the height H of the dielectric body preferably amounts to at least 50% of the maximum thickness D of the dielectric body; further preferably, in this respect, the height H of the dielectric body amounts to at least 70% of the maximum thickness D of the dielectric body. A correspondingly larger displacement of the radiation plane is hereby given.
In possible embodiments, the height H of the dielectric body can amount to more than 85% of the maximum thickness D of the dielectric body or even more than 150%. The height H of the dielectric body is at least not limited upwardly in principle. However, H<6*D preferably applies, further preferably H<3*D, with respect to the intended application.
In this respect H<3*D preferably applies to antennas having a horizontal full width half maximum between 55° and 100°, in particular to antennas having a horizontal full width half maximum of 65°+−10° or 90°+−10°. Alternatively or additionally, in this respect, H<6*D and/or H>2*D applies to antennas having a horizontal full width half maximum between 23° and 43°. The directivity effect of the dielectric body that increases with a larger height is hereby taken into account.
It is furthermore conceivable in beam-forming and/or beam-shaping applications in which a plurality of antennas can be flexibly connected to one another and/or can be operated separably, to use dielectric bodies having different heights for the individual antennas.
In accordance with the invention, the height H of the dielectric body is measured in the main radiation direction of the dipole radiator. The thickness D is measured in the cross-section of the dielectric body, i.e. in a plane perpendicular to the main radiation direction of the dipole radiator. The dielectric body in this respect does not have to have a symmetrical configuration. The longest extent of the dielectric body in the main radiation direction of the dipole radiator is considered as the height of the dielectric body and the longest extent in cross-section, i.e. in a plane perpendicular to said main radiation direction, is considered as the thickness of the dielectric body in a vertical plane. The maximum thickness D of the dielectric body is thus the largest thickness, viewed over all vertical planes, in a cross-section of the dielectric body.
The cellular radio antenna in accordance with the invention is preferably connectable to a cellular radio base station via signal lines to receive and/or to transmit cellular radio signals. In this respect, the cellular radio antenna in accordance with the invention can be used in a frequency band that is in the range between 100 MHz and 10 GHz, preferably between 500 MHz and 6 GHz. Alternatively or additionally, the antenna can have a resonant frequency range that is between 100 MHz and 10 GHz, preferably between 500 MHz and 6 GHz. In principle, higher frequencies are also conceivable, in particular when the dipole radiator is a printed circuit dipole.
The dielectric body in accordance with the invention can first be produced from any desired dielectric material. For example, the dielectric body can be produced from a homogeneous dielectric material. The dielectric body can, for example, in this respect be a solid plastic body.
Alternatively, the dielectric body can, however, also comprise a first material having a higher relative permittivity and a second material having a lower relative permittivity. For example, in this respect, the first material can be embedded in the second material as a granulate, or vice versa. Alternatively, the second material can be gaseous and can be embedded in bubble-form in the first material. Air bubbles can in this respect in particular be provided in the first material.
Independently of the material used, the dielectric body preferably has an effective relative permittivity εr of more than 2, further preferably of more than 2.5. The effective relative permittivity εr can in this respect, for example, be between 2 and 4, further preferably between 2.5 and 3.5.
For example, solid material having a relative permittivity in this range can be used in this respect or material having a higher relative permittivity and embedded air holes. Material having a higher relative permittivity can furthermore be embedded as a granulate in a material having a lower relative permittivity, for example.
The material of the dielectric body can in this respect have an approximately constant permittivity or a gradient of permittivity.
The dielectric body preferably has an axis of symmetry facing in the main radiation direction. A particularly uniform far-field diagram hereby results.
The symmetry is in this respect particularly preferably an axial symmetry and/or a rotational symmetry. The dielectric body is in this respect particularly preferably rotationally symmetrical with respect to an axis of symmetry aligned in the main radiation direction of the dipole radiator, i.e. it has a round cross-section. In this case, the maximum thickness D corresponds to the maximum diameter of a cross-section of the dielectric body.
Alternatively, the dielectric body can be axially symmetrical with respect to an axis of symmetry aligned in the main radiation direction of the dipole radiator, for example with a cross-sectional area in the form of a preferably regular polygon, for example of a quadrangle or a square. In this case, the maximum thickness D corresponds to the maximum diagonal of a cross-section of the dielectric body.
The dielectric body preferably has a rod region. The thickness of the dielectric body preferably differs in this rod region by a maximum of 30%, and further preferably by a maximum of 15%, from the maximum thickness D. In this respect, the largest extent of the dielectric body in a vertical plane is understood as the thickness of the dielectric body in said vertical plane. Alternatively or additionally, the cross-sectional area of the dielectric body preferably differs in the rod region by a maximum of 30%, and further preferably by a maximum of 15%, from the maximum cross-sectional area of the dielectric body.
The dielectric body preferably has a cross-section in every vertical plane, at least in the rod region, that comprises a circle or a preferably regular polygon, for example a quadrangle, a hexagon, an octagon, etc. In principle, however, any form having a waveguide function and/or aperture displacement function is conceivable.
The dielectric body particularly preferably has a thickness that is constant in the vertical direction and/or a cross-section that is constant in the vertical direction in the rod region. The rod region in particular has a cylindrical shape, preferably a circular cylindrical shape or parallelepiped shape.
The height of the rod region preferably amounts to between 50 and 100%, further preferably to between 65 and 100%, of the height H of the dielectric body.
Alternatively or additionally, the dielectric body can have a lens region. In the lens region, the dielectric body preferably has a cross-section varying in the vertical direction. The cross-sectional area of the dielectric body preferably varies in the lens region by at least 30% in the lens region and further preferably by at least 50% with respect to the maximum cross-sectional area of the dielectric body.
The lens region particularly preferably has the form of a truncated cone or of a truncated counter-cone or of a truncated pyramid or of a truncated counter-pyramid. The smallest diameter or the smallest diagonal of the truncated cone or counter-cone or of the truncated pyramid or counter-pyramid in this respect particularly preferably amounts to between 30 and 80% of the maximum diameter or of the maximum diagonal of the truncated cone or counter-cone or of the truncated pyramid or counter-pyramid, further preferably to between 40 and 70%.
The height of the lens region preferably amounts to between 5 and 50%, preferably to between 10 and 35%, of the height H of the dielectric body.
The dielectric body preferably has both a rod region and a lens region. The lens region is in this case preferably arranged on the side of the rod region remote from the dipole radiator. Alternatively, the dielectric body can only have a rod region with a cross-section varying slightly in the vertical direction.
Independently of the specific form of the dielectric body, the latter is preferably arranged in the main radiation direction on the dipole radiator. No dielectric body is further preferably provided in the region of the dipole radiator itself, i.e. the dipole radiator is not embedded in the dielectric body, but rather arranged on the dielectric body in the main radiation direction.
In this respect, in accordance with the invention, the dielectric body can be directly placed onto the dipole radiator and can in particular be in contact therewith or can be arranged separately therefrom via a narrow gap of preferably no more than 2 mm.
If the dielectric body has an axis of symmetry, it preferably coincides with the axis of symmetry of the dipole radiator. In this respect, an axis that extends in the main radiation direction and with respect to which the dipole segments forming the dipole radiator are symmetrically arranged is understood as the axis of symmetry of the dipole radiator.
The dipole radiator in accordance with the invention is preferably a dual-polarized dipole radiator. The inventors have recognized in this respect that a dielectric body can be used as a waveguide for both polarizations of such a radiator. The two polarizations of the radiator preferably stand orthogonally on one another and/or have separate ports for the supply with cellular radio signals.
The two dipoles of the dual-polarized dipole radiator preferably have the same axis of symmetry, with the two dipoles preferably being arranged in a criss-cross manner with respect to the common axis of symmetry. It can, for example, be a dipole square.
The dipole radiator preferably has a base region that extends in the main radiation direction and has dipole segments that are arranged on the base region and that preferably extend perpendicular to the main radiation direction.
The dipole radiator used in accordance with the invention can comprise one or more additional radiators that are optionally also based on different radiation principles. One or more additional radiators can in particular be integrated in the dipole radiator. For example, the dipole radiator can have one or more slots that act as slot radiators so that from an electrical aspect the dipole radiator used in accordance with the invention is a combination of a dipole radiator and a slot radiator.
In a preferred embodiment of the present invention, the following relationship exists between the maximum thickness D and the height H of the dielectric body, the wavelength λ of the center frequency of the lowest resonant frequency range of the antenna and the relative permittivity εr of the dielectric body:
                              0.5          *                      (                          λ                                                π                  ⁡                                      (                                                                  ɛ                        r                                            -                      1                                        )                                                                        )                          ≤        H                                                            and        ⁢                  /                ⁢        or                                                                      0.5          *                      (                          λ                                                π                  ⁡                                      (                                                                  ɛ                        r                                            -                      1                                        )                                                                        )                          ≤        D        ≤                  2.5          *                                    (                              λ                                                      π                    ⁡                                          (                                                                        ɛ                          r                                                -                        1                                            )                                                                                  )                        .                                                          
The following relationship particularly preferably applies:
                    ⁢                  0.75        *                  (                      λ                                          π                ⁡                                  (                                                            ɛ                      r                                        -                    1                                    )                                                              )                    ≤      H            and    ⁢          /        ⁢    or              0.75      *              (                  λ                                    π              ⁡                              (                                                      ɛ                    r                                    -                  1                                )                                                    )              ≤    D    ≤          2.5      *              (                  λ                                    π              ⁡                              (                                                      ɛ                    r                                    -                  1                                )                                                    )            ⁢                          ⁢      or        ⁢                  ⁢                  ≤          1.25      *                        (                      λ                                          π                ⁡                                  (                                                            ɛ                      r                                        -                    1                                    )                                                              )                .            
In this respect,
                              D          ≤                      1.5            *                          (                              λ                                                      π                    ⁡                                          (                                                                        ɛ                          r                                                -                        1                                            )                                                                                  )                                      ,                        preferably                                    D          ≤                      1.25            *                          (                              λ                                                      π                    ⁡                                          (                                                                        ɛ                          r                                                -                        1                                            )                                                                                  )                                      ,            preferably applies to antennas having a horizontal full width half maximum between 55° and 100°, in particular to antennas having a horizontal full width half maximum of 65°+−10° or 90°+−10.
Alternatively or additionally, the following applies to antennas having a horizontal full width half maximum between 23° and 43° or to antennas having a relative bandwidth of more than 40°:
  D  ≤      2.5    *                                                                  _            .      
It is taken into account in this respect that a larger multiplier may be required for the diameter in comparison with the wavelength for a very high directivity or bandwidth.
In this respect, a resonant frequency range is understood within the framework of the present invention as a contiguous frequency range of the radiator that has a return loss of better than 6 dB or better than 10 dB or better than 15 dB. The selected limit value of the return loss in this respect depends on the specific use of the antenna. The center frequency is defined as the arithmetical mean of the highest and lowest frequency in the resonant frequency range.
The resonant frequency range and thus the center frequency are preferably determined in accordance with the invention with respect to the impedance position in the Smith chart, while assuming the following elements for an ideal impedance matching and/or impedance transformation.
Within the framework of the use of the antenna in accordance with the invention, the lowest resonant frequency range is preferably understood as the lowest resonant frequency range of the antenna used for transmission and/or reception.
It has been found in this respect that a particularly effective displacement of the radiation plane can be achieved by the above-indicated dimensioning since the dielectric body works particularly well as a waveguide.
The directional effect of the dielectric body can, on the one hand, be influenced by the use of different body shapes and body sizes. A combination with a conductive and/or metallic element is furthermore conceivable to influence the properties of the antenna.
A conductive and/or metallic element is preferably arranged in accordance with the invention in and/or at the dielectric body. The directivity effect can in particular be influenced by such metallic elements.
In a first variant, the conductive and/or metallic element can be a coating of an inner or outer surface of the dielectric body. In a second variant, it can be a conductive and/or metallic disk arranged in or at the dielectric body. Both variants can be combined with one another.
Provision can alternatively or additionally be made that the conductive and/or metallic element surrounds an outer periphery of the dielectric body. It can in this respect in particular be a metalization of the outer periphery of the dielectric body. The conductive and/or metallic element can alternatively extend in a plane perpendicular to the main radiation direction. A metal disk is particularly preferably used in this case that extends in a plane perpendicular to the main radiation direction of the dipole radiator. Such a metallic disk can in this respect, for example be arranged between a rod part and a lens part of the dielectric body.
The conductive and/or metallic element can in particular be used to improve the directivity effect in frequency ranges in which the directivity effect of the dielectric body is less strong.
In accordance with the invention, the conductive and/or metallic element has a directivity effect that is at a maximum for a frequency fmet. The dielectric body furthermore preferably has a directivity effect that is at a maximum for a frequency fdiel. In accordance with the invention, the frequencies fmet and fdiel differ in this respect. The directivity effect of the conductive and/or metallic element and the directivity effect of the dielectric body are hereby at a maximum for different frequency ranges such that the far-field properties of the antenna in accordance with the invention are improved by the combination of dielectric body and conductive and/or metallic element over a larger frequency range.
The frequency fmet is in this respect preferably smaller than the frequency fdiel. The conductive and/or metallic element is thus optimized for smaller frequencies; the dielectric body for larger frequencies.
Alternatively or additionally, the frequency fmet can in this respect be smaller than the center frequency fres of the lowest resonant frequency range of the antenna and the frequency fdiel can be larger than this center frequency fres.
Further alternatively or additionally, there can be a certain spacing between the two frequencies fdiel and fmet. The following relationship preferably applies in this respect:|fdiel−fmet|/fdiel>0.1*fdiel, further preferably |fdiel−fmet|/fdiel>0.2*fdiel.
The antenna in accordance with the invention preferably has a reflector on which the dipole radiator is arranged. The reflector preferably has a conductive reflective plane that stands perpendicular on the main radiation direction of the dipole radiator.
In a possible embodiment, the reflector can have a subreflector. This subreflector is preferably configured as a reflector frame. In a particularly preferred embodiment, the edge length of the reflector frame is larger than the maximum thickness D of the dielectric body.
In a further possible embodiment, the spacing between the dipole radiator and the reflector can be between 0.05λ and 0.5λ, preferably between 0.1λ and 0.4λ. λ is in this respect the wavelength of the center frequency of the lowest resonant frequency range of the antenna.
In a further possible embodiment, the reflector can have a directivity effect that is at a maximum for a frequency fref. The dielectric body furthermore preferably has a directivity effect that is at a maximum for a frequency fdiel, with the two frequencies fref and fdiel not coinciding. The directivity effect is hereby reached over a larger frequency range since the reflector and the dielectric body each bundle ideally for different frequency ranges.
In accordance with a first subvariant, the frequency fref can be smaller than the frequency fdiel, i.e. the reflector is adapted for smaller frequencies than the dielectric body.
In a second subvariant, the frequency fref can be smaller than the center frequency fres of the lowest resonant frequency range of the antenna and the frequency fdiel can be larger than the center of the frequency fres.
In a third subvariant, there can be a specific spacing between the frequency portions fdiel and fref. In this respect, |fdiel−fref|/fdiel>0.1*fdiel is in particular preferred; further preferably |fdiel−fref|/fdiel>0.2*fdiel.
The above-named embodiments and variants with respect to the reflector can each be implemented per se. The variants are, however, preferably combined with one another.
The antennas in accordance with the invention can in particular be used together with further antennas as a component of an antenna arrangement.
The present invention comprises in a second aspect a cellular radio antenna arrangement having a plurality of antennas, in particular for a cellular radio base station, having a first subgroup of one or more first antennas and a second subgroup of one or more second antennas. In this respect, the first antennas each comprise a dipole radiator having a first dielectric body arranged on the dipole radiator, wherein the height H1 of the first dielectric body amounts to at least 30% of the maximum thickness D of the first dielectric body. The second antennas each comprise a radiator without a dielectric element or with another, second dielectric element. In this respect, in particular a plurality of first antennas are preferably used.
The inventors of the present invention have recognized in this respect that the use of dielectric bodies in cellular radio antenna arrangements having a plurality of antennas allows an influencing of the far-field values of the cellular radio antenna arrangement. In particular since the dielectric bodies can only be used in a first subgroup of radiators or since different dielectric bodies are used for different subgroups of antennas, the effective radiation plane of the respective radiators of the subgroup are changed.
In this respect, a plurality of first antennas are preferably provided, wherein the dipole radiators of the first antennas have identical resonant frequency ranges. The first antennas can in this respect in particular be used for operation in the same cellular radio frequency band. In a preferred embodiment, the dipole radiators of the first antennas are preferably identical.
Provision can alternatively or additionally be made that the dipole radiators of the first antennas have the same radiation plane and/or height HS1 above a common reflector. This allows a simple interconnection of the dipole radiators of the first antennas and thus of the first antennas.
Provision can furthermore be made in accordance with the invention that a plurality of second antennas are provided, wherein the radiators of the second antennas have identical resonant frequency ranges. The second antennas can hereby be used for operation in the same cellular radio frequency band. In a preferred embodiment, the radiators of the second antennas are preferably identical.
Alternatively or additionally, the radiators of the second antennas can have the same radiation plane and/or height HS2 over a common reflector. A simple interconnection of the radiators of the second antennas and thus of the second antennas is hereby possible.
Provision can furthermore be made that the first dielectric bodies of the first antennas each have the same height H1. The first dielectric bodies are furthermore preferably identical to one another. The first dielectric bodies thus influence the radiation characteristics of the radiators of the first antennas in respectively the same manner.
Provision can furthermore be made that the second dielectric bodies, where they are used, each have the same height Hz. The second dielectric bodies are furthermore preferably identical to one another. The second dielectric bodies hereby also influence the radiation of the radiators of the second antennas in respectively the same manner.
The first dielectric bodies preferably differ from the second dielectric bodies, where they are used, in particular with respect to their height. The first and second dielectric bodies thus influence the radiation of the dipole radiators of the first antennas and the radiators of the second antennas in respectively different manners.
An embodiment is particularly preferred in which only first dielectric bodies are used and the radiators of the second antennas do not have a dielectric element.
In a preferred embodiment of the present invention, the dipole radiators of the first antennas are dual-polarized dipole radiators. The space within the cellular radio antenna arrangement is hereby ideally used.
The radiators of the second antennas can furthermore be dual-polarized radiators. Alternatively or additionally, the radiators of the second antennas can be dipole radiators. The radiators of the second antennas can in particular be dual-polarized dipole radiators. The present invention is, however, likewise used with different radiators of the second antennas.
The first subgroup of antennas of the antenna arrangement in accordance with the invention can have separate ports for transmitting and/or receiving cellular radio signals. The first subgroup of antennas can thus in particular be used separately from the second subgroup of antennas for transmitting and/or receiving cellular radio signals.
Alternatively, the first subgroup and the second subgroup of antennas of the antenna arrangement in accordance with the invention can, however, also have common ports for transmitting and/or receiving cellular radio signals.
Provision can be made in accordance with the invention that the antennas of the first subgroup and/or the antennas of the second subgroup each form one or more group antennas and have common ports for transmitting and/or receiving cellular radio signals.
The first antennas of the first subgroup can in this respect in particular be interconnected to form one or more group antennas. The first antennas of the first subgroup can in particular in this respect be connected to one or more common ports via one or more phase shifters.
In the same manner, the second antennas of the second subgroup can form one or more group antennas and can in particular be connected to one or more common ports via one or more phase shifters.
In an alternative embodiment, the antennas of the first subgroup can each have separate ports for transmitting and/or receiving cellular radio signals. Alternatively or additionally, the antennas of the second subgroup can also each have separate ports for transmitting and/or receiving cellular radio signals. Beam-forming or beam-shaping applications are possible due to the separate ports of the individual antennas. The individual antennas can in particular in this respect preferably be interconnected to form different group antennas and/or can each be operated individually for separate channels.
The use in accordance with the invention of dielectric bodies has advantages with many different antenna arrangements. Depending on the embodiment of the antenna arrangement, the dielectric bodies can in this respect be used to displace the radiation planes of the respective subgroups of antennas away from one another or to move them toward one another or to increase the radiation plane of lower arranged antennas to improve their radiation characteristics.
In a first variant of the cellular radio antenna arrangement in accordance with the invention, the dielectric bodies shift the radiation planes of the first antennas and of the second antennas away from one another. In this respect, the first dielectric bodies can in particular be used to move the radiation plane of the first antennas away from the radiation planes of the second antennas. The coupling of the first antennas and of the second antennas in the cellular radio antenna arrangement is hereby reduced.
Such a shift of the radiation planes is in this respect in particular used when the dipole radiators of the first antennas and the radiators of the second antennas are arranged in a common plane and/or have the same height HS above a common reflector. In this case, the radiators of the first and second antennas would per se have the same radiation planes. It is, however, achieved by the use of dielectric bodies that the first antennas have a different radiation plane than the second antennas. In this respect, the radiation plane of the first antennas is in particular raised above the radiation plane of the second antennas.
In this respect, the shift V of the radiation plane by the first dielectric body and the height HS of the dipole radiators of the first antennas above a common reflector preferably have the following relationship: 0.5 HS>V. Alternatively or additionally, the height H1 of the first dielectric bodies and the height HS of the dipole radiators of the first antennas above a common reflector have the following relationship: 0.5 HS>H1.
The shift in accordance with the invention of the radiation planes can in this respect in particular be used in a cellular radio antenna arrangement in which the dipole radiators of the first antennas and the radiators of the second antennas have the same resonant frequency ranges and/or have the same structure. Depending on the specific application purpose, the first and second antennas can in this respect be used for the same or for different cellular radio bands. Even if the dipole radiators of the first antennas and the radiators of the second antennas in this respect have the same resonant frequency ranges and/or have the same structure, the resonant frequency ranges of the individual antennas formed by the radiators and the dielectric bodies can nevertheless differ since the use of the dielectric bodies also has an influence on the resonant frequency ranges of the antenna formed by radiators and dielectric bodies.
A shift in accordance with the invention of the radiation planes can in this respect be used both when the antennas of the first and second subgroups each form one or more group antennas and when the antennas of the first and second subgroups each have separate ports for transmitting and receiving cellular radio signals. In a further possible embodiment, the first and second antennas can be interconnected together to form one or more group antennas.
In a further embodiment variant of the present invention, the dielectric bodies move the radiation planes of the first antennas and of the second antennas toward one another. The first dielectric bodies can thus be used to move the radiation plane of the first antennas toward the radiation plane of the second antennas.
Such a movement of the radiation planes toward one another is in this respect in particular used when the dipole radiators of the first antennas and the radiators of the second antennas are arranged in different planes and/or have different heights HS1 and HS2 above a common reflector. With such an arrangement, the dipole radiators of the first antennas and the radiators of the second antennas in principle have different radiation planes. This spacing between the radiation planes of the radiators can be reduced by the use of the dielectric bodies.
In a preferred embodiment, the nevertheless remaining spacing A between the radiation planes has the following relationship to the height HS1 of the first dipole radiators above a common reflector: A>0.5 HS1, preferably A>0.2 HS1. In this respect, the spacing A can also completely become 0, i.e. the radiation planes are equalized with respect to one another.
Such a movement toward one another of the radiation planes is preferably used when the dipole radiators of the first antennas and the radiators of the second antennas have the same resonant frequency ranges and/or have the same structure. Such an embodiment is furthermore preferably used when the dipole radiators of the first antennas and the radiators of the second antennas are interconnected together to form one or more group antennas. The radiation plane of the individual radiators of a group antenna formed by dipole radiators of the first antennas and radiators of the second antennas can in particular hereby be approximated to one another.
In a third variant of the present invention that can be combined with the first and/or second variant, the dipole radiators of the first antennas are arranged in a first plane and the second antennas have metal structures that are arranged in a second plane above the first plane. Provision is made in this respect that the first dielectric bodies extend at least up to the second plane of the metal structures of the second antennas and/or raise the radiation plane of the dipole radiators of the first antennas to at least the second plane. It is thus prevented by the use of the dielectric bodies that the metal structures of the second antennas impair the radiation characteristics of the dipole radiators of the first antennas in a manner such as was frequently to be found in the prior art.
Such an embodiment is in particular used when the height HS1 of the dipole radiators of the first antennas above a common reflector is smaller than the height HS2 of the radiators of the second antennas above the common reflector.
Such an embodiment can furthermore in particular be used when the center frequency of the lowest resonant frequency range of the dipole radiators of the first antennas is higher than the center frequency of the lowest resonant frequency range of the radiators of the second antennas or when the first antennas are used for radiating in a higher frequency band than the second antennas. In this case, the radiators of the second antennas are typically larger than the dipole radiators of the first antennas and therefore project over the dipole radiators of the first antennas. Due to the shift in accordance with the invention of the radiation plane of the dipole radiators of the first antennas due to the use of the first dielectric bodies, their radiation power can be substantially improved since they are less pronouncedly influenced by the radiators of the second antennas.
In a possible embodiment, the radiators of the second antennas can be configured as dipole radiators and can be arranged in a plane above the plane of the dipole radiators of the first antennas. The radiators of the second antennas can in particular have bases in this respect that are higher than the bases of the dipole radiators of the first antennas such that the dipole segments of the radiators of the second antennas arranged on the bases are arranged above the dipole segments of the radiators of the first antennas. In this case, the first dielectric bodies are designed such that they project at least up to the dipole segments of the dipole radiators of the second antennas and preferably beyond them. In this case, the first and second antennas are preferably used for different frequency bands and/or have different resonant frequency ranges.
The second antennas can in this respect comprise a plurality of dipoles that are arranged in the shape of a square and/or of a cross and/or of a T.
In a further embodiment that can be combined with the above-described embodiment, third radiators can be arranged in the region of the radiators of the second antennas. These third radiators preferably have the same resonant frequency range and/or are used for the same frequency band as the dipole radiators of the first antennas. Alternatively or additionally, the dipole radiators of the first antennas and the radiators of the second antennas can have different resonant frequency ranges and/or can be used for different frequency bands.
By the arrangement of the third radiators in the region of the radiators of the second antennas, said radiators can typically not have the same plane as the dipole radiators of the first antennas. The third radiators can in this respect in particular be arranged on radiators of the second antennas and can thus be arranged on a different plane than the dipole radiators of the first antennas. Further alternatively or additionally, the dipole radiators of the first antennas are arranged between the radiators of the second antennas.
In such an embodiment, the first dielectric bodies have a dual function. On the one hand, they improve the radiation possibilities of the first antennas since the radiators of the second antennas impede the radiation of the dipole radiators of the first antennas less due to the shift of their radiation plane. Furthermore, the radiation plane of the dipole radiators of the first antennas is approximated to the radiation plane of the third radiators by the first dielectric bodies.
In a possible embodiment, the radiators of the second antennas can have radiator elements that extend in parallel with and/or perpendicular to and/or obliquely to the radiation direction. In this respect, the third radiators can be arranged within the radiator elements extending in parallel with and/or perpendicular to and/or obliquely to the radiation direction. Alternatively or additionally, the third radiators can be dual-polarized radiators.
The dipole radiators of the first antennas and the third radiators can have the same structure.
The last-described embodiment of a cellular radio antenna arrangement can in particular be used when the dipole radiators of the first antennas and the third radiators of the first antennas are interconnected and/or interconnectable to form a group antenna. The dipole radiators of the first antennas and the third radiators can in this respect in particular be combined via one or more phase shifters to form one or more group antennas.
The cellular radio antenna arrangement in accordance with the invention preferably comprises at least one column or row of antennas, wherein the first and second antennas are arranged alternately in the column or row and/or wherein the second antennas are arranged between two columns or rows of first antennas. The group antenna can in this respect in particular have a plurality of columns and rows, with the first and second antennas each being alternately arranged in the plurality of columns and rows, and/or with the second antennas being arranged between a plurality of columns and rows of first antennas.
The cellular radio antenna arrangement can furthermore have a housing within which the first and second antennas are arranged. The cellular radio antenna arrangement furthermore preferably has ports via which the cellular radio antenna arrangement is connectable to a cellular radio base station. Phase shifters can furthermore be provided in the housing via which antennas of the cellular radio antenna arrangement are interconnected to form group antennas.
In a cellular radio antenna arrangement in accordance with the second aspect of the present invention, cellular radio antennas such as have been described in more detail in accordance with the first aspect of the present invention are preferably used as first antennas.
This in particular relates to the configuration and/or dimensioning of the first dielectric bodies of the first antennas that is/are preferably carried out as shown above with respect to the first aspect.
The second antennas can in this respect admittedly in principle likewise be designed in accordance with the first aspect of the present invention. The second antennas, however, preferably do not have any dielectric bodies and are accordingly not configured in accordance with the first aspect of the present invention.
The present invention will now be shown in more detail with reference to embodiments and to drawings. There are shown: